User churn in serious games related to Chinese cultural heritage is severe due to various game quality issues, leading to a lack of long-term user feedback necessary for optimizing design, which further hampers the development of such games. Through user interviews and literature review, this study identified two dimensions of quality of cultural heritage serious games: factors related to online gaming and those intrinsic to serious games. Within the Stimulus-Organism-Response (SOR) theoretical framework of, this study integrates these quality factors within the Technology Acceptance Model (TAM) to construct a user churn model. This model explores the relationship between quality factors and user churn. Utilizing 534 valid responses gathered from online platforms, this study employs statistical analyses and structural equation modeling to uncover that learning objectives, entertainment experience, system quality, and game design profoundly influence both perceived usefulness and ease of use, which in turn indirectly impacts user churn. Service quality’s influence on user churn is mediated by perceived usefulness, while brand image affects churn through perceived ease of use. Notably, learning objectives and entertainment experience emerge as critical determinants. The insights gained offer valuable guidance for game designers in addressing user needs, enhancing game quality, and reducing churn. Building on previous research, this study uses a mixed-methods approach and identifies factors affecting user churn in the context of cultural heritage serious games and validated the model’s rationality and effectiveness, enriching the foundational theoretical research on serious games.